<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./vuejs/vue.js"></script>
</head>
<body>
    <div id="app">
        <div>{{a}}</div>
        <div>{{obj.b}}</div>
    </div>
    <script>
       var vm = new Vue({
           el:'#app',
           data:{
               a:'233',
               obj:{}
           }
        });

        Vue.set(vm.obj,'b','qwq');
    </script>
</body>
</html>